Simplify. Remove all perfect squares from inside the square root. $\sqrt{52x^4}=$
Factor $52$ and find the greatest perfect square: $52=2\cdot 2\cdot 13=2^2\cdot 13$ Find the greatest perfect square in $x^4$ : $x^4=\left(x^2\right)^2$ $\begin{aligned} \sqrt{52x^4}&=\sqrt{2^2\cdot 13\cdot \left(x^2\right)^2} \\\\ &=\sqrt{2^2}\cdot \sqrt{13} \cdot \sqrt{\left(x^2\right)^2} \\\\ &=2\cdot \sqrt{13} \cdot x^2 \\\\ &=2x^2\sqrt{13} \end{aligned}$